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Bray and Davar 3: These three best fit equations were obtained based on in-bank flows corresponding to 2-year flood flows from 67 gravel-bed river reaches in Alberta, Canada (Bray, 1979). These three equations are used for estimating average velocity for high in-bank flows in gravel-bed rivers and the authors suggested that two or more independent approaches should be used and that the results should be compared.

Bray, D.I., and Davar, K.S., 1987, Resistance to flow in gravel-bed rivers; Canadian Journal of Civil Engineering, volume 14, pp 77-86.

Bray, D.I., 1979, Estimating Average Velocity in Gravel-Bed River: Journal of the Hydraulics Division, Proceedings of the American Society of Civil Engineers, vol. 105, no. HY9, September, 1979: pp. 1103-1122.

n N-value.
R Hydraulic radius in meters.
d84 Bed material diameter corresponding to that 84 percent of the material is finer, units in millimeters, mm.
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